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What is WebSphere eXtreme Scale?

WebSphere eXtreme Scale operates as an in-memory grid that dynamically processes, partitions, replicates, and manages application data and business logic across hundreds of servers. It provides transactional integrity and transparent fail-over to ensure high availability, high reliability, and consistent response times. WebSphere eXtreme Scale is an essential distributed caching platform from IBM for elastic scalability and the next-generation cloud environments.

Elastic means the grid monitors and manages itself, allows scale-out and scale-in, and is self-healing by automatically recovering from failures. Scale-out allows memory capacity to be added while the grid is running, without requiring a restart. Conversely, scale-in allows on-the-fly removal of memory capacity. Read more about elasticity, and how eXtreme Scale provides it, here.

WebSphere eXtreme Scale is an in-memory cache for storing objects. It's designed to store lots of objects efficiently. One term we use is "linear scaling". This means as we add more objects to our cache, or access the objects more frequently, we don't want our access time and system throughput to degrade. We want to handle this increased load as seamlessly and transparently as possible. For example, as we add load, we want to be able to add another machine to our grid to handle the extra load without any other changes. Certainly our existing users and applications should not notice. They should continue to see good response times. To use other parlance, linear scaling is the ultimate in horizontal scale-out. We want each additional processor to be fully utilized, and contribute its full power to additional end-user processing with no tax or overhead incurred.

How do I get started quickly?

1. Elastic Caching with eXtreme Scale This 4 minute video describes how eXtreme Scale provides grids that scale elastically, meaning that they transparently scale out to add capacity and scale in to recover from failures.
2. eXtreme Scale Usage Patterns A brief (4 minute) video introduction to eXtreme Scale with a description of the four basic usage patterns: 1. application state store (including HTTP Session Management), 2. Side Cache, 3. In-line Cache (Database Shock Absorber), 4. Extreme Transaction Processing (XTP). Find out more at What WebSphere eXtreme Scale can do for you
3. See Lesson 1 below for background concepts, especially:
   1. Partitioning -- The key to Linear Scaling
   2. Replication -- The key to High Availability
   3. Zones -- Controlling shard placement Is an [Advanced Topic] that may be skipped on first reading.
4. Getting Started: Understanding eXtreme Scale and how it works is another introductory background article that gives an overview of WebSphere eXtreme Scale.
5. Get if you need a free trial version of the product.
   • This is the full product and you can play with it for free! The only catch with this version of the product is that you have to reboot it after it runs for 8 hours. That is quite long enough for developing samples and giving the tires a real good kick! See this video of Billy and Rob describing the trial version. It is always up to date, but is a standalone version. It does not have the WebSphere Application Server integration features.
6. Get right into working code with the Getting Started sample, which performs basic create, read, update, and delete (CRUD) operations from the command line in a client-server environment. The sample ships with the product and appears in the gettingstarted/ directory of your installation.
7. See Lesson 2 below.
8. See the Samples Gallery for more samples.
9. See IBM Extreme Transaction Processing (XTP) Patterns: Leveraging WebSphere Extreme Scale as an in-line database buffer, Lan Vuong's excellent article about write-through caching: how to do it, code, and measured results. Published 6/3/2009. See Billy and Rob discuss work behind this article in this video.
10. See Principles and best practices for building high performing and highly resilient WebSphere eXtreme Scale applications by four IBM Distinguished Engineers, including WebSphere eXtreme Scale Chief Architect Billy Newport. Published 4/14/2010.

Lessons

Lesson 1: Partitioning, Replication, Shards and Zones

1. Partitioning -- The key to Linear Scaling
2. Replication -- The key to High Availability
3. Zones -- Controlling shard placement [Advanced Topic]

See the Elastic Caching with eXtreme Scale video that covers the first two topics in 4 minutes, describing how eXtreme Scale provides grids that scale elastically, meaning that they transparently scale out to add capacity and scale in to recover from failures.

Lesson 2: Introducing the Programming APIs

1. Introducing the GettnStarted Sample Application
   • GettnStarted Sample Application Installation and Setup
2. Code for the ObjectMap Sample
3. Code for the EntityManager Sample

Lesson 3: Performance Tuning and Considerations

1. Performance Tuning and Considerations

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